Scroll-Type Fluid Machine Lap Clearance Thermal Deformation

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Solution Overview

Problem

In scroll-type fluid machines, thermal deformation causes lap clearance changes, leading to potential contact between scroll parts and increased leakage, which worsens performance.

Innovation Solution

The implementation of concave and convex portions on the lateral surfaces of the lap parts to manage thermal deformation, preventing contact and leakage by adjusting the lap clearance, with concave portions reducing the risk of contact and convex portions preventing clearance widening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the lap clearance is reduced to improve compression efficiency, then compression efficiency is improved, but the laps may come into contact due to thermal deformation

Engineering Contradiction:
Improvecompression efficiencyVSAvoidrisk of lap contact
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention applies different clearance designs to different regions of the lap part. Specifically, the clearance varies along the spiral direction, with smaller clearance in regions less prone to thermal deformation and larger clearance in regions more susceptible to thermal expansion. This localized differentiation allows the system to maintain tight clearances for efficiency while providing extra space where thermal deformation is most likely to cause contact.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the clearance parameter along the spiral direction of the lap part. By making the clearance variable rather than uniform, the design adapts to the thermal deformation patterns that occur during compression operation. The clearance is optimized at different positions to balance compression efficiency and prevent lap contact.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the lap clearance is increased to prevent contact, then reliability is improved, but leakage of compressed fluid increases

Engineering Contradiction:
Improveprevention of lap contactVSAvoidleakage of compressed fluid
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

Rather than uniformly increasing clearance throughout the lap part, the invention applies increased clearance only in specific regions where thermal deformation is most pronounced. Other regions maintain smaller clearances to minimize leakage. This selective approach preserves compression efficiency while preventing contact in the critical areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The clearance parameter is changed strategically along the spiral direction, increasing it only where thermal deformation poses a contact risk. This localized parameter change prevents energy loss from excessive leakage while maintaining reliability by preventing lap contact in the most vulnerable regions.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If uniform clearance is used for simplicity, then manufacturing is easier, but thermal deformation causes either contact or leakage

Engineering Contradiction:
Improveclearance uniformityVSAvoidcompression efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The invention moves from uniform clearance to locally differentiated clearance along the spiral direction. While this increases manufacturing complexity slightly, it significantly improves compression efficiency and prevents both contact and leakage by adapting the clearance to the thermal deformation characteristics of different regions.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances performance and reliability by maintaining optimal lap clearance, preventing contact and leakage, thereby improving compression efficiency.

Implementation Method 1

compressed air, which has been compressed to have an increased temperature, heats the laps and the lap clearance changes due to thermal deformation

Methodology Applied
Scientific EffectThermal deformation: Thermal Expansion

Data Source

PatentEP3306096B1Scroll-type fluid machine
Publication Date: 2024.03.13 HITACHI IND EQUIP SYST CO LTD
  • EP3306096B1 patent drawingFigure 1(A)~1(E)
  • EP3306096B1 patent drawingFigure 2~3
  • EP3306096B1 patent drawingFigure 4~6

AI summary

The present invention makes a lap clearance between a fixed scroll and an turning scroll as small as possible to suppress leakage of compressed fluid from a compression chamber in a compression operation, thereby improving a compression efficiency. Provided is a scroll-type fluid machine characterized by comprising: a fixed scroll having a scroll lap portion; and an orbiting scroll that is provided to face the fixed scroll and that has a scroll lap portion turning so as to form a plurality of compression chambers in a clearance relative to the lap portion of the fixed scroll, wherein the lap portion of at least one of the fixed scroll and the turning scroll is provided with, in a predetermined region, a recessed portion on one lateral surface thereof and a protruding portion on the other lateral surface thereof.